Firing device for combustion apparatus



Aug. 30,- 1949. s. LETVIN FIRING DEVICE FOR COMBUSTION APPARATUS 2 Sheets-Sheet 1 Filed Jan. 29, 1947 25 :fpY- j IIIH lllH

FIG.

ATTORNEY Aug. 30, 1949. s. LETVIN 2,480,147 v FIRING DEVICE FOR COMBUSTION APPARATUS Filed Jan. 29, 1947 2 SheetsSheet 2 FIG..2

INVENTOR.

SAMUEL LETVIN ATTORNEY Patented Aug. 30, 1949 UNITED STATES PATENT OFFICE FIRING DEVICE FOR COMBUSTION APPARATUS Samuel Letvin, New York, N. Y. Application January 29, 1947, SerialNo. 724.93g

2 Qlaims. (01. 158-28) (Granted under the act of March 3, 1883, as

amended April .30, 1928; 370 0. G. 757) 1 This invention relates to firing devices. The invention provides a novel firing device that is particularly adapted to fire combustion I chambers operating at high pressures, although it is applicable as well to firing boiler furnaces, burners and other combustion apparatus.

An object of the invention is to provide a firing device having a continuously projected flame, that operates on the same iuel as that employed in the principal burner and that has its entire mechanism outside oi. the chamber, burner or vessel to be fired.

Another object is to provide a firing device capable of functioning over a wide range of combustion chamber pressures, for example, from zero to 100 ounds per square inch.

Another object is to provide a firing device in which control is simple and requires only that a higher pressure he maintained at the air inlet to the atomizer of the device than exists in the combustion chamber, and that the fuel pressure to the atomizer be sumcient to cause the fuel to flow to the device and be atomized.

The nature of the invention will be understood from the following description when considered in connection with the accompanying drawings forming a part thereof, and in which:

Fig. l is a transverse sectional view of a combustion chamber having a firing device of the invention,

Fig. 2 is a sectional view along Fig. i,

Fig. 3 is a longitudinal sectional view of the outer end portion of the firing device,

Fig. 4 is an enlarged longitudinal sectional view oi? the atomizer shown in Fig. 3, i

Fig. 5 is a sectional view on line 5-5 of Fig. 4, on an enlarged scale, and

Fig. 6 is a sectional view on line 6-6 of Fig, 3.

The firing device designated generally it, is shown in association with a combustion chamber it for firing the burner i2. The combustion chamber has a cylindrical air casing II at one end thereof, to which air is supplied through an inlet i4, and from which the air flows around the burner difluser it to mix with the atomized oil discharged from the burner tip I.

The firing device It comprises generally an atomizer section Ill and a tubular flame-conducting section i8. Fuel for the atomizer is supplied through a feed line It and is forced by a pump 20 through line 2| and through control valve 22 to the atomizer connection 23. Pump 2| maintains a pressure on the fuel which is sumcient to cause the fuel to fiow to the atomizer line 22 of and be atomized. Excess fuel delivered by pump 20 flows through pressure release valve 24 and through return line 25 to the feed line l9. Fuel delivered to the interior of the connection 23 flows through the barrel 26 to the nozzle body 21 of the atomizer and through three longitudinally extending passages 28 in the outlet end portion of the body 21 to the outer ends of three tangential slots 29 that deliver the fuel into the chamber 30 of the sprayer plate 3| wherein it rotates rapidly and from which it is discharged in the form of a spray through opening 32 into the ignition zone 33 of the atomizer section l1.

Sprayer plate 3! is maintained in position against the nozzle body 21 by an atomizer tip 34 that is threaded on the and of the body 21.

Air is supplied to the firing device through a supply line 35 to a blower 36'which forces the air through line 31 and through a regulator valve 38, thence through line 39 and control valve 4|] to the atomizer section ll. The air enters flange 42 and flows thro igh a passage 4| in the flange to an annular chamber 43 that is disposed around a part of the barrel 26 adjacent its end. The air 25 fiows from the chamber 43 through an annular passage 44 between the barrel 2B and a primary air tube 45 that is outside of and conentric with the barrel 26, and is discharged into an enlarged annular space 46 between the nozzle body 21, the tip-34 of the atomizer and the inner end portion of a secondary tube 41 that is outside of, spaced from, and concentric with the primary air tube 45. The barrel 26, nozzle body 2'7, atomizer tip 34, the primary and secondary tubes 45 and 41, and the ignition zone 33 are enclosed by a tube 48 that is spaced from and is concentric with the secondary tube 41.

The several parts of the atomizing section are maintained in position in the manner shown. The connection 23 has its inner end threaded into the outer side of flange 42 and the outer end of barrel 26 is threaded into the connection 23 and thus the barrel and atomizer are supported in position with respect to the flange 42. Primary air tube 45 has its outer end threaded into the inner side of the flange 42. The outer end of the secondary tube 4'! has an annular flange 49 welded thereto and positioned between the flange 42 on one side and on the other side the outer end of tube 48 and a cup-shaped flange 50 welded thereto. Flanges 42, 49 and 50 are held together by bolts 5| that extend from flange 50 through flange 42 and have nuts 52 threaded thereon.

The pressure existing in the combustion chamber l I is transmitted to one side oi the diaphragm 3 of the regulating valve II by a static line [3. The regulating valve is set to maintain a pressure of about one pound per square inch above the pressure in the combustion chamber. A gauge 6| indicates the pressure existing in air line 39.

The fuel and air mixture delivered to the ignition zone 33 is ignited by two spark plugs 55 and 58 to which high-tension current is supplied by transformers 51 and 58, respectively, that receive current .from the line 59. The flame so produced flows through flame conducting section i8, to a point to the rear of the diffuser I! of the burner l2, where it is discharged toward the diffuser and flows around it and into contact with the ignitable fuel-air mixture issuing from the burner. Tubular section it is connected to the atomizer section I! by bolts 60 and nuts ii that secure together a triangular flange 62 welded to the inlet end of the section It! and a triangular flange 63 welded to theoutlet end of the tube 48.

This firing device operates on the same type of fuel that is supplied to the burner l2, thereby eliminating the necessity for maintaining a separate supply of a different fuel. The fuel is supplied to the firing device with sufficient pressure by pump 20 to cause the fuel to be atomized, and air is supplied to the igniter by blower 36 in a quantity that is sufliciently in excess of the amount of fuel to permit proper combustion to be maintained in the ignition zone 33. Flame is projected continuously from the discharge end of the tube l8, thus ensuring the firing of the burner l2. The firing device functions over a wide range of combustion chamber pressures, at least from zero to 100 pounds per square inch. Control of the firing device requires only that (1) a higher pressure he maintained at the air inlet to the atomizer than that existing in the combustion chamber, which is ensured by the operation of the regulating valve 38, and that (2) the fuel pressure to the atomizer be sufllciently in excess of the combustion chamber pressure to cause the fuel to flow to the atomizer and be atomized, which is ensured by the operation of pump 20.

The fiame discharging end of the firing device need not be positioned up-stream of the burner l2 as shown, so long as it is located so that the flame from the firing device readily ignites the air-fuel mixture from the principal burner or burners of the installation with which the igniter is used. Such principal flames can also be generated by causing the pilot or secondary flame from the firing device to enter the zones in the wake of or downstream from the burner, or to be projected through an orifice in the difluser of the burner to the region contiguous to the atomizer orifice of the burner.

It is to be understood that various modifications andchanges may be made in this invention without departing from the spirit and scope thereof as set forth in the appended claims.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

What is claimed is:

1. In combustion apparatus, means forming a combustion chamber and a firing device therefor, said device comprising an atomizer having a discharge port; a first tubular member for supplying fuel to said atomizer, fuel-inlet means in the first tubular member; a second tubular member coaxial with the first tubular member and outside of and spaced from the first tubular member, the space between said members forming an air-supply passage, air-inlet means connecting with said passage, the second tubular member terminating short of the atomizer discharge port;

a third tubular member coaxial with the second tubular member and outside of and spaced from the second tubular member, the third tubular member extending slightly beyond the atomizer discharge port; and a fourth tubular member coaxial with the third tubular member and outside of and spaced from the third tubular member, the fourth tubular member at one end extending beyond the third tubular member into the combustion chamber to define an ignition zone, an igniter in said zone, said fourth tubular member at the other end being sealed relative to the second tubular member.

2. In combustion apparatus, means forming a combustion chamber and a firing device therefor, said device comprising an atomizer having a discharge port; a first tubular member for supplying fuel to said atomizer, fuel-inlet means in the first tubular member; a second tubular member coaxial with the first tubular member and outside of and spaced from the first tubular member, the second tubular member terminating short of the atomizer discharge port, the space between said members forming an air-supply passage, airinlet means connecting with said passage; a third tubular member coaxial with the second tubular member and outside of and spaced from the second tubular member, the third tubular member extending slightly beyond the atomizer discharge port, the space between the third tubular member and the atomizer being in communication with the air-supply passage and forming an enlarged air chamber; a fourth tubular member coaxial with the third tubular member and outside of and spaced from the third tubular member, the fourth tubular member at one end extending beyond the atomizer to define an ignition zone, an igniter in said zone, the fourth tubular member at the other end being sealed relative to the second tubular member to prevent ingress of .fiuid to the ignition zone externally of the second tubular member; and a flame guide at one end forming a fluid seal with the fourth tubu- 7 lar member and at the other end extending into the combustion chamber.

SAMUEL LETVIN.

REFERENCES CITED The following references are of record in the file of this patent:

v UNITED STATES PATENTS Number Name Date 1,316,021 Doble Sept. 16, 1919 2,047,523 Scranton et al July 14, 1936 2,069,498 Lang et a1 Feb. 2, 1937 2,285,704 Frank June 9, 1942 2,407,973 Beckstrom Sept. 24, 1946 

